ALIASES:

BackDoor-BAC (McAfee); Backdoor.Haxdoor (Symantec); Trojan.Win32.Generic!BT (Sunbelt); Backdoor.Hupigon.11789 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 431,616 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 01 Jan 2013

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\LdShih\
LsFileExplorer

It adds the following registry entries:

HKEY_CURRENT_USER\Software\LdShih\
LsFileExplorer
ParentImgIdx = "5"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KernelCheck
ImagePath = "\??\%User Temp%\KpCheck.sys"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\KernelCheck
Type = "1"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\system\CurrentControlSet\
Services\KernelCheck\Security

HKEY_LOCAL_MACHINE\system\CurrentControlSet\
Services\KernelCheck

HKEY_LOCAL_MACHINE\system\CurrentControlSet\
Services\KernelCheck\Enum

Dropping Routine

This backdoor drops the following files:

  • %User Temp%\KpCheck.sys

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\LdShih
    • LsFileExplorer

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\LdShih\LsFileExplorer
    • ParentImgIdx = "5"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KernelCheck
    • ImagePath = "\??\%User Temp%\KpCheck.sys"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\KernelCheck
    • Type = "1"

Step 4

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
  • %User Temp%\KpCheck.sys

Step 5

Scan your computer with your Trend Micro product to delete files detected as BKDR_AGENT.DOW. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 6

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_LOCAL_MACHINE\system\CurrentControlSet\Services\KernelCheck
    • Security
  • In HKEY_LOCAL_MACHINE\system\CurrentControlSet\Services
    • KernelCheck
  • In HKEY_LOCAL_MACHINE\system\CurrentControlSet\Services\KernelCheck
    • Enum


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